Magneto-electric ignition apparatus



March 31, 1931. w, wALTHER 1,798,571

MAGNETO ELECTRIC IGNITION APPARATUS Filed Sept. 4, 1925 I Fig.7 Fig.2

Patented Mar. 31, 1931 UNITED STATES PATENT OFFICE WILHELM WALTHER, 0F STUTTGAR'I', GEItMANY, ASSIGNOR TO ROBERT BOSCH AKTIEN- GESELLSCHAFT, 0F STUTTGART, GERMANY MAGNETO-ELECTRIC IGNITION APPARATUS Application filed September 4, 1925, Serial No. 54,488, and in German-y October 10, 1924.

My invention relates to magneto-electric ignition apparatus; more particularly it relates to a rotor for use in connection with electromagnetic ignition apparatus having a stationary coil and a rotary permanent magnet; and the object or" my invention is to design an apparatus of'the kind stated in which the rotor is composed of a plurality of permanent magnets of very simple con- W tours which are perfectly alike and have only caslng as is all more fully described hereinafter.

My invention is illustrated by way of example in the accompanying drawings in which Figure l is a longitudinal section through a magneto-electric ignition apparatus designed according to this invention; Figure 2 is a cross-section on line- A-B of Fig. 1; Figure 3 is a longitudinal section on line C-D of Fig. 1; Figs. 4 and 5 show a modification having an overhanging rotor, Fig. 4 being an axial section on line 4-4 of Fig. 5, and Fig. 5a front elevatiomon reduced scale, of. the modified rotor construction as viewed from the left end of Fig. 4.

Referring to Figs. 13, the rotor is composed, firstly, of two non-magnetic plates 0 and I), each of which is provided with a journal or equivalent member 0. Pole shoes d, composed of pieces of sheet metal, are riveted to plate a. Non-magnetic ring 6 is also riveted to plate a and serves to stiffen the pole shoes against radial forces. All these members form, in their entirety, a casing, into which are inserted thereinto flat bar magnets or straight magnets f. Each of these magnut 1'.

by suitably shaped projections h on the plate 0, (Figs. 2 and 3) these projections also serving to center the pole-shoes and to hold the edges of the magnets in alinement with said pole shoes. Axial displacement of the magnets is prevented by the plate I) which is connected with the projections in by screws 2'. These projections are a little shorter or lower than the combined thickness of the magnets f, in consequence whereof the plate 6 is pressed by the screws 2' against the magnets rather than against the projections. Radially, the plate 5 is maintained in proper position by the ring 6.

' The other members of the apparatus are designed, arranged, and combined as in the known apparatus. I have omitted them, except the armature it, its coil m, and the casing at.

It will be obvious that the magnets of the constructional form shown and described have very simple contours, and can, therefore, be easily punched, and are not likely to warp. They are all alike which is very important from the standpoint of economy in quantity production. Besides, they need fit accurately only at their circularly curved portions, and there may be left, without scruple, a certain clearance or play between the magnets and the projections 72.. It is also immaterial whether they all are of the same thickness as they are being held together firmly by the plate I), and if the rotor should not, perhaps,

fit accurately between the collars of its bearings, it is feasible either to re-finish said collars or to employ shims, both means being much cheaper than the working or re-workin of the hard magnets.

%f the rotor is overhanging, as inFigs. 4 and 5, the second plate (1)) may be replaced by a bow 0 secured by screws 1) to the pro] ections it. The shaft 0 is connected firmly with the other plate (a) and secured in place by a.

In this constructional form t hc magnets f each have a bore g for the admission of til) said nut r,,but these bores need not fit accurately relative to each other. Finally, a flat spring 8 is inserted bet-ween'the bow 0 and the adjacent magnet in order to keep the magnets f in their proper position. Such a spring may be employed also with the constructional form shown in Figs. 1-73.

I claim: 7

1. A rotor for use in connection. with a magneto-electric ignition apparatus having a stationary coil, comprising a non-magnetic rotary plate having oppos tely located projections extending parallel to the axis of said plate, said pole shoes having smooth circular interior faces; annularly curved pole-shoes.

afiixed to'said plate; permanent magnets extending between said pole-shoes parallel to said plate, said magnets being located between said projections, as set forth.

. comprising, a plate, pole shoes aflixed to said 2. A rotor for use in connection with a magneto-electric ignition apparatus having a stationary coil, comprising anon-magnetic rotary plate; annularly curved pole-shoes affixed to said plate, said pole shoes having smooth circular interior faces; permanent between sa d pole-shoesmagnets extendin parallel to said p ate; and a spring so arranged as to exert upon said magnets an axial pressure in the direction of the said plate, substantially as set forth.

3. A rotor for an ignltion device of the stationary coil and revoluble magnet type plate, said pole shoes havin smooth circular interior faces, a pluraht o magnets extending between said pole s oes, means integral with said plate for maintaining said magnets in alinement'with said pole shoes, and

means secured to said plate for clamping said magnets in position, said clamping means in- .cluding a spring member adapted to exert an axialressure on said magnets. 1

4. rotor for an ignition device of the stationary coil and revoluble magnet type comprising, a non-magnetic plate, circularly curved, segment-shaped pole shoes aflixed to said plate, said pole shoes having smooth circular interior faces, a non-magnetic rin for bracing said pole shoes against centri gal force, a second non-magnetic late mounted vto rotate with-said first mentioned plate, a

plurality of permanent magnets inte' osed I v between said plates, the end portions 0 said magnets contacting with the inner cylindrical surfaces of said pole shoes, and rigid connecting means between said plates, said connecting means being integral with one of said' plates and forming, with said pole shoes and plates, a housing conforming to the contour of said magnets.

In testimony whereof I have hereunto affixed my signature.

' WILHELM WALTHER. 

